This is an application for a five-year competing renewal of a Population Research Center Core Grant to the Center for Demography and Ecology (CDE) at The University of Wisconsin-Madison. CDE is a multi- disciplinary faculty research cooperative for social scientific demographic research whose membership includes sociologists, rural sociologists, economists, anthropologists, and historians. CDE provides research support through four Cores: administration, data processing, data library and print library. Current and planned research activities of CDE focus on population composition and distribution within the United States, especially on changes in family structure and process and social inequality, but the total range of research and training activities of CDE members is far broader in content and scope. CDE activities include about 20 approved research projects; in addition to these projects, CDE has NICHD and NIA support for predoctoral and postdoctoral training in population and support from the Hewlett foundation for international population training and research. CDE members typically have overlapping memberships in cooperating research and training units, which include their academic departments, the Institute on Aging and Adult Life, the Institute for Research on Poverty, the Applied Population Research Laboratory, and the Letters and Sciences Survey Research Laboratory. CDE has been and plans to remain a leader in efficient management and analysis of large, complex demographic data files. The central theme of this proposal, beyond maintenance of current core support capabilities, is to establish an infrastructure for centralized archival storage and retrieval, combined with distributed data processing, that will preserve and enhance our capability to manage and analyze our current data holdings and the influx of data from the 1990 round of Censuses, especially that of the United States. In order to build CDE's capacity for these changes in technology and organization, we are proposing a program development project in data storage and retrieval.